Apparatus for forming a continuous reinforced flexible hose



March 28, 1967 L.. E. CARPENTER ETAL 3,311,523

APPARATUS FOR FORMING A CONTINUOUS REINFORCED FLEXIBLE HOSE Filed March25. 1964 4 Sheets-Sheet l ATTORNEYS March 28, 1967 L.. E. CARPENTER ETAL3,311,523

APPARATUS FOR FORMING A CONTINUOUS REINFORCED FLEXBLE HOSE 4sheets-sheet2 Filed March 25, 1964 ff s mmz .d mWenwN NmpZ/l Mx Mm lEfmh MJ [LfMarch 28, 1957 l.. E. CARPENTER ETAL 3,311,523

APPARATUS FOR FORMING A CONTINUOUS REINFORCED FLEXIBLE HOSE 4Sheets-Sheet Filed March 25, 1964 alCh 28, 1957 l.. E. CARPENTER ETAL.3,311,523

APPARATUS FOR FORMING A CONTINUOUS REINFORCED FLEXIBLE HOSE' Filed March25, 1964 4 Sheets-Sheet 4 Richard Peley Joseph T. HZL

United States Patent O 3,311,523 APPARATUS FR FORMING A CNTINUUSREINFRCED FLEXIELLE I-ISE Lester E. Carpenter, Vernon, Conn., Richard B.Pelley, East Kingston, N.H., and `oseph T. Hall, Stamford, Conn.,assgnors to Callahan Mining Corporation, New Yorii, N.Y.

Filed Mar. 25, 1964, Ser. No. 354,525 I3 Claims. (Cl. 156-429) Thisinvention relates to a method and apparatus for making flexible hose andto flexible hose. More particularly, it relates to a flexible hose ofthe type formed as a series of overlapping helical loops of wirereinforced tape. The tape used in hose of this type typically has anadhesive coating along one longitudinal edge and a reinforcing springwire is secured to the tape along its other longitudinal edge.

In the prior art method `and apparatus for manufacturing hose of thistype, the tape, with reinforcing wire adjacent one edge, is fed from acontinuous supply to a pair of nip rolls. The nip rolls are both,iournalled at one end in a suitable frame member and extend in parallelrelation from that frame member, their opposite ends being free. Thewire reinforced tape, after passing between the nip rolls, is loopedback on itself and its free end again fed between the nip rolls inoverlapping relation to the adhesive edge of the tape just enteringbetween the nip rolls. The nip rolls are continuously rotated to windthe tape, as well as the wire secured thereto, into a series of helicalloops. The loops are adhesively sealed together at their overlappingedges by the pressure of the nip rolls as the tape passes therebetween.The hose thus continuously formed gradually feeds axially ofrr the freeends of the nip rolls.

In the hose produced according to this prior art method and apparatus,the reinforcing wire in the hose has a tendency to contract axially,thereby contracting the hose; this may cause the hose to creep away fromits desired location. Thus, for example, where the hose is employed todeliver fresh air to a user Working in an oxygen scarce area, or wherethe hose is used to exhaust air therefrom, it may contract, pulling itsfree end away from the worker with resultant loss of fresh air. Suchcontraction of the hose also results in a wrinkling and twisting of thefabric, producing an unsightly appearance and tending to impede the freepassage of gases through the hose.

Several attempts have been made to solve this problem of hosecontraction. For example, a heavier fabric tape has been used to resistthe tendency of the Wire helix to contract. To some extent, thisresisted contraction, but the resulting hose was stiff and could not becollapsed lengthwise easily; it therefore required excessive storage andshipping space. Such hose was also difficult to dispose and maintain inany curved configuration.

Hose has also been made by forming a length of spring wire into a helixof greater pitch than that desired in the final hose. Then the wirehelix was elastically compressed to the desired pitch. Thereaftersuccessive loops of tape fabric 4were stitched to the compressed wirehelix so that the resulting hose was pre-stressed and was continuouslybiased toward its full length. This hose, however, was not adaptable tohigh speed manufacture and the resulting stitch holes in the tapeweakened the hose and allowed gas leakage. lso, stitching produced aselvage edge which projected into the interior of the completed hosewhere it restricted gas ow through the hose.

Accordingly, it is an object of the present invention to provide animproved method and apparatus for the continuous manufacture of flexiblehose of the wire reinforced type.

ICC

It is a more specific object of the present inventionl to provide amethod and apparatus of the above character' for the continuousmanufacture of flexible wire reinforced hose of the pre-stressed type.

It is a further object to provide a wire reinforced hose of the abovecharacter having relatively smooth internal and external wall surfaces.l

It is a still further object to provide a wire reinforced pre-stressedhose of the above character which is less subject to fatigue failurethan known hoses of this type.

lt is yet another object to provide a wire reinforced pre-stressed hoseof the above character which is initially more lluid tight than knownhoses of this type and which will retain its fluid tightness even overperiods of sustained usage.

Other objects of the invention will in part be obvlous and will in partappear hereinafter.

Theinvention according-ly comprises the several steps and the relationof one or more of such steps with respect to each of the others, theapparatus embodying features of construction, combinations andarrangements of parts which are adapted to effect such steps, and thearticle which possesses the characteristics, properties and relation ofelements, all as exemplilied in the detailed disclosure hereinafter setforth, and the scope of the invention will Ibe indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

FIGURE 1 is a fragmentary perspective view of a flexible wire reinforcedhose produced according to the method of, and by the apparatus of, thepresent invention;

FIG-URE 2 is a view of `an apparatus for the continuous manufacture ofthe hose of FIGURE l,

FIGURE 3 is an enlarged fragmentary sectional view taken on line 3 3 ofFIGURE 2,

FIGURE 4 is a perspective View of the apparatus shown in FIGURE 2,

FIGURE 5 is a side elevational view looking from the right of FIGURE 2and taken on line 5-5 of that figure,

FIGURE 6 is a side elevational view looking from the right of FIGURE 2,and

FIGURE 7 is a fragmentary sectional View looking from the left of FIGURE6 and taken on line 7-7 of that figure. l

The hose ofthe invention, as seen most clearly in FIG- URE 1, comprisesa strip 1li of flexible tape fabric having a side edge portion 12 foldedover onto and secured to the main body portion 14 of the fabric. Thefabric strip is wound helically to form a continuous tube with thefolded edge portion 12 lying at the inner surface of the tube andoverlapping, for each convolution, the unfolded side edge portion 16 ofthe adjacent convolution. The unfolded side edge kportion 16 of eachconvolution, in addition to being secured to and overlapped by thefolded edge portion of the adjacent convolution, passes beyond thefolded edge portion for securement to the main body portion 14- of thefabric. The hose further comprises a helically Wound spring wire 1Slodged in the fold of the fabric to reinforce the finished hose.

In the production of the above described hose by the method andapparatus of the present invention, the tape fabric 10 and spring wire18 are fed continuously and simultaneously to a folder generallyindicated at 20 where the side edge portion 12 of the advancing tape `isfolded over the wire i8 to form a tape having a wire reinforcement alongone side edge. The wire reinforced tape is thereafter fed continuouslyby suitable means to a forming zone generally indicated at 22 where thetape and wire are bent upwardly and then twisted, thereafter advancingthrough a helical path to a bonding zone indicated generally at 24. Herethe tape and wire helix is elastically compressed axially and theoverlapped edges of the compressed tape sealed together to form apre-stressed hose.

As will be seen in FIGURES 2 and 4, the folder 20 comprises a folderplate 26 secured as by a bracket 23 to the main frame member 30 of theapparatus. The tape is fed continuously to the plate 26 from a rollsupp-ly (not shown) and is provided with adhesive coatings on the upperface of its side edge portion 12 and on the lower face of its side edgeportion 16. The wire 18 is fed continuously to the folder plate 26 froma spool supply (not shown) along a 4path lying immediately above thepath of the advancing tape and parallel to, but spaced from, the sideedge of the advancing tape. As the tape and wire are advanced togetherover and along the folder plate 26, the side edge portion 12 of the tapeis engaged and gradually folded over the wire by an upturned end 32 ofthe Vfolder plate. The tape with the wire lodged in the fold of the sideedge portion 12 is thereafter advanced between two sets of groovedcoacting nip rollers 34 and 36 which. are journalled in frame member 3i)and driven in tandem by a suitable chain and gear system indicatedgenerally at 37. Roller sets 34 and 36 firmly bond the adhesive sideedge portion 12 to the main -body portion 14 of the tape fabric and actto pull the tape and wire through the folder from their respectivesupply sourcesA The grooves 34a and 36a in the roller sets 34 and 36 arealigned with the path of travel of the wire 18 so that as the tapefabric passes between the rollers of each set the folded edge of thetape fabric holding the wire is received in the grooves.

From the roller sets 34 and 36 the wire reinforced tape is pushed to andbetween a relatively small diameter grooved upper idler roller 3-8(FIGURE 4) coacting with a relatively large diameter grooved lower idlerroller 4i). Rollers 3'3 and 4t) are journalled respectively on a pair ofelongated shafts 42 and 44 which in turn are joumalled in the framemember 39. Shafts 42 and 44 extend in parallel relation laterally awayfrom frame member 3i) and have free ends 46 and 48 as seen in FIGURE 4.Located beyond the idler rollers 38 and 4() in the direction of movementof the tape is a grooved idler roller 50 journalled in frame member 30forwardly of idler rollers 38 and 40. As best seen in FLGURE 5, theperiphery of roller 50 is above the bite of the idler rollers 38 and 40.Another grooved idler roller 52 is journalled in the frame member 30forwardly of and below idler roller 5) with the upper portion of itsperiphery slightly above the lower portion of the periphely of roller50. Thus the tape and wire bend upwardly between the idler rollers 5!and 52, and this bending action imparts a permanent arc-like shape tothe wire, as can best be seen in FIGURE 5.

To provide an adjustment' of the radius of this bend, and hence theultimate diameter of the resulting hose, the idler roller 52 is mountedon an adjustable carriage plate 54. Plate 54 is slidably mounted betweenupper and lower tracks S6 and is connected to a screw 6? threaded in anut 62 on the frame member 30. Thus, the relative position of rollers 50and 52 may be determined by turning handle 58 secured to screw 60.

Referring now to FIGURES 2, 4 and 5, the advancing tape now curlsupwardly from the rollers 59 and 52, to engage a deflector plate 64mounted on the frame member 30 by a bracket 66. Deector plate 64 isarranged to present a at deecting surface 68 (FIGURE 4) lying obliquelyabove and laterally outwardly of the idler rollers 50 and 52. Theconfiguration 4and positioning of the surface of the plate 64 are suchas to continuously twist the tape and wire leaving the rollers 5t) and52. The plate 64 thus forces and bends the tape and wire into a helicalpath winding successively around the upper elongated shaft 42 (FIGURE 2)which eventually feeds each convolutio-n between upper and lower formingrollers 7) and 72 (FIGURE 4), as will be presently described. The

bending action imparted to the advancing wire and tape by the rollers 5)and 52 and the twisting action imparted thereto by the plate 64 are suchas to plastically defor-m the wire. In this manner rollers 50 and 52 andplate 64 coact to impart a permanent diameter and pitch to the wire.

Bracket 66 is mounted on a suitable adjustable support 67 for universalmovement with respect to fra-me member 30, whereby the angle of thedeecting surface 68 to the arcuate path taken by the tape and wire incurling upwardly may be selectively varied.

The relatively small diameter upper forming roller 70 is fixedly securedto the free end 46 of shaft 42 and the coacting relatively largediameter lower forming roller 72 is iixedly secured to the free end 48of shaft 44. Shafts 42 and 44 and rollers 70 and 72 are rotated inopposite directions by a suitable chain and gear system generallyindicated at 74 in FIGURE 2. Rollers 70 and 72 are provided withcoacting grooves 76, 77, 78 and '79 axially spaced therealong by adistance which is less than the pitch imparted to the advancing tape bythe deflector plate 64 and associated mechanism; this distance is alsoless than the width of the advancing tape.

Coacting grooved rolls 8*!) and 81 are arranged to receive therebetweenthe wire reinforced edge of the tape advancing helically from thedeflector plate 64. The rolls Si) and 81 are mounted on the free end ofa 4bracket 82. The bracket 82 is mounted at its other end on a post 83about which it is Iadjustable to vary the position of the rolls inrelation to the position of plate 64. The rolls and S1 are positioned toguide the advancing tape between the nip rollers 70 and 72 with thefolded wire reinforced edge received in the coacting grooves 76 and 77.

As the tape emerges from the coacting grooves 76 and 77, it is engagedsuccessively by a plurality of grooved roll pairs 84 arranged seriallyaround an arcuate shaped mounting bracket 86 as best seen in FlGURES land 4. Bracket 86 is adjustably mounted on post 83. The seriallyarranged roll pairs 34 engage the folded wire reinforced edge of theadvancing tape and guide the tape back between the forming rolls 7@ and72 with lthe folded edge now received in the coacting grooves 78, 79.Since the axial distance between grooves 76, 77 and grooves 78, 79 isless than the tape width, as tihc folded edge of the tape enters grooves'73, 79, it overlaps and is pressed against the adhesive unfolded sideedge portion i6 of the convolution just entering the grooves 76. 77 asis shown in FIGURE 7. The successive convolutions of the advancing tapeare thus ad'hesively bonded together at the grooves 7S, 79 to form acontinuous hose. A rubber sleeve 83 on the free end of the roll 72increases the bonding pressure exerted by rolis 76 and 72; byresiliently deforming in the bonding zone, lthis sleeve increases thearea over which the bonding action is effected. The hose thus formedfeeds continually off the free end 46 of the forming roll 7i) fordelivery to suitable apparatus (not shown) for further handling.

Since the spacing between the grooves 76, 77 and the grooves 78, 79 isless than the pitch imparted by the deflector plate 64 to the advancingtape, by forcing each convolution of the advancing tape to enter firstbetween the grooves 76, 77 and then between the grooves 78, 79 thepermanently formed wire helix lodged in the fold of the advancing tapeis compressed in the direction of its length. Since this compression ofthe wire helix is in the nature of a gradual constraint exertedincrementally by the successive roll pairs S4, the wire helix iselastically rather than plastically compressed. With the wire helix inthis elastically compressed condition, the successive convolutions oft-he tape are then bonded together so that in the finished hose the wirehelix continuously resiliently biases the hose to its full length. Thusthe finished hose, while it may be readily compressed for storage andshipping purposes, normally extends itself to its full length andexhibits no tendency to contract or shorten in use` It should be notedin the apparatus herein provided that whereas the tape and wire arepulled from their respective sources through the folder 2t), they arepushed through the forming zone 22 by the nip rollers 34, 36. That is,the tape and wire are being pushed at the time they undergo theabove-described bending and twisting operations. This is importantbecause it is essential that la positive control be maintained on thestresses of the tape and wire during such bending and twisting. lf thetape and wire were pulled through the forming zone, the opposing forcesacting on them would .tend to change due, for example, to variations inthe amount of wire remaining on the supply spool or variations in theconsistency of the adhesive occurring as a result of variations ofambient humidity or temperature. With the present arrange ment ofpushing the tape and wire through the forming zone, suc'n variationsproduce no appreciable change in the forces acting on the tape andfabric. It will of course be understood that suitable means (not shown)are provided to synchronize the operation of the nip roller drive means37 and the forming roller drive means 74 so that the tape and wire willbe taken up and discharged by the forming rollers '70, 72 at preciselythe rate at which it is being pushed through the forming zone by the niprollers 34, 36.

It will thus be seen that the objects of the invention, as previouslyset forth, have been fully met by the method, apparatus and producthereinabove disclosed. That is, we have provided an improved method andapparatus for .the continuous manufacture of fiexible hose of the wirereinforced type and, more specificaliy, we have provided a method andapparatus whereby flexible reinforced hose of t-he pre-stressed type maybe continuously manufactured at production line speeds. Further, we haveprovided a wire reinforced hose of the pre-stressed type which is fiuidtight and extremely durable, having a continuous firmly bonded adhesiveseam rather .than a series of spaced and fabric weakening stitches. Itwill further be seen that we have provided a hose of the wire reinforcedtype in which both the internal and external walls are relatively smoothso as to afford relatively little resistance to the passage of gasesthrough the hose or over the external surface of the hose.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding descrip- Ition, are efficiently attainedand, since certain changes m'ay be made in carrying out the abovemethod, in the described product, and in the construction set forthwithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings sh'all be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features ofthe invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

We claim:

1. An apparatus for forming a continuous pre-stressed flexible hose froma continuous flexible strip having a continuous reinforcing spring wiresecured thereto substantially adjacent one edge thereof comprising (A)means for continuously plastically deforming the wire reinforced stripinto a first helical path,

(B) first and second forming rollers, at least one of said rollershaving first and second annular grooves therein,

(C) said forming rollers being mounted for rotation about parallel axes,the fiexible strip being passed from said first helical path betweensaid rollers with its wire reinforced edge received in said first grooveand being thereafter looped around one of said rollers with its wirereinforced edge received in said second groove in a selected mount ofoverlapping with the other edge of said strip,

(D) and means for continuously counter rotating said rollers,

(E) said first and second grooves being spaced apart axially by adistance different from the pitch of said first helical path so thatsaid strip is elastically constrained to achieve said selected amount ofoverlapping.

2. An apparatus for forming a continuous pre-stressed flexible hoseIfrom a continuous fiexible strip having an adhesive longitudinal edge,and a continuous reinforcing spring wire secured thereto substantiallyadjacent its other longitudinal edge, comprising (A) means forcontinuously plastically deforming the wire reinforced strip into afirst helical path,

(B) first and second forming rollers, at least one of said rollershaving first and second annular grooves therein,

(C) said forming rollers being mounted for rotation about parallel axes,lthe fiexible strip being passed from said first helical path betweensaid rollers with its wire reinforced edge received in said first grooveand being thereafter looped around one of said rollers for repassagebetween said rollers with its wire reinforced edge received in saidsecond groove in a selected amount of overlapping with the adhesive edgeo-f said strip,

(D) and means for continuously counter rotating said rollers,

Y (E) said first and second grooves being spaced apart axially by adistance different from the pitch of said first helical path so thatsaid strip is elastically constrained to achieve said selected amount ofoverlapping said axial distance,

(F) said axial distance bei-ng less than the Width of 5 said strip sothat the strip loop received at its reinforced edge in said first-groove laps the strip loop received at its reinforced edge in saidsecond groove and said rollers coact to press the lapped adhesive edgeof one of said loops against the reinforced edge of the other of saidloops, whereby to form a continuous pre-stressed hose.

3. An apparatus according to claim 2, said axial dis tance being lessthan the pitch of said first helical path so that said wire iselastically compressed in, and longitudinally tensions, `the completedhose.

4. An apparatus according to claim 1 wherein both said first and secondforming rollers have said first and second lannular grooves therein,

(A) said rollers being mounted with the first and second grooves in oneroller aligned with the respective grooves in the other roller.

5. An apparatus for forming a continuous hose from a continuous strip offiexible wire reinforced material comprising (A) means for feeding saidstrip material continuously along a substantially straight line path,

(B) means mounted transversely of the plane of said path and engagingsaid strip material as the latter moves along said path to bend it outof said plane for movement in an arcuate path,

(C) and a deliector member extending across the plane of said arcuatepath at an obtuse angle thereto to engage said strip material as thelatter moves along said arcuate path and twist it out of said arcuatepath plane for movement in a helical path.

6. An apparatus for forming a continuous hose from a continuous strip offiexible wire reinforced material comprising (A) means defining asubstantially straight line feeding path for said strip material,

(B) coating rollers disposed on either side of said path so that saidstrip material is passed therebetween in its movement along said path,

(C) a first bending roller disposed ahead of said coacting rollers andhaving a peripheral surface tracing an orbit intersecting the plane ofsaid path, thereby to engage the strip material as the latter movesalong said path to bend it out of said plane for movement in an arcuatepath,

(D) and a defiector member presenting a deflection surface extendingacross the plane of said arcuate path at an obtuse angle thereto toengage said strip material as the latter moves along said arcuate pathand twist it out of said arcuate path plane for movenient in a helicalpath.

7. An apparatus according to claim 6 and further including a secondbending roller disposed ahead of said coacting rollers and behind saidfirst bending roller and having a peripheral surface tracing an orbitlying completely to one side of and spaced from said straight line pathplane, said strip material after passing between said coacting rollersbeing threaded between said first and second bending rollers which bendthe strip material and move it into said arcuate path.

y3. An apparatus for forming a pre-stressed flexible hose from aflexible strip having a continuous reinforcing spring wire securedt-heret-o substantially adjacent one edge thereof, comprising (A) meansdefining a substantially straight line feeding path for said stripmaterial,

(B) first and second elongated shafts journalled at their one ends andextending in parallel relation transverse to and on either side of saidpath,

(C) first and second coacting rollers on said first and second shafts,respectively, said strip material passing between said rollers in itsmovement along said path,

(D) means engaging said strip material at a location lbeyond saidrollers and operative to continuously plastically deform said stripmaterial into a first helical path winding successively `around one ofsaid shafts toward the free end of the latter,

(E) first and .second forming rollers secured to said first and secondshafts adjacent their respective free ends, at least one of said formingrollers having first and second annular grooves therein, the strip material being passed from said first helical path between said formingrollers with its -wire reinforced edge received in said first groove andbeing thereafter looped around the `forming roller on said one shaft forrepassage between said forming rollers with its wire reinforced edgereceived in said second groove in a selected amount of overlapping withthe other edge of said strip,

(F) and means for continuously counter rotating said shafts and therebysaid forming rollers,

(G) said first :and second grooves being spaced apart axially by adistance different from the pitch of said first helical path so thatsaid strip material is elastically constrained to achieve said selectedamount of overlapping.

9. An apparatus -for forming a pre-stressed liexible `hose from afiexible strip having an adhesive longitudinal edge, and a continuousreinforcing spring wire secured thereto substantially adjacent the otherlongitudinal edge thereof, comprising (A) means defining a substantiallystraight line feeding path for said strip material,

(B) first and second elongated shafts journalled at their one ends andextending in parallel relation transverse to and on either side of saidpath,

(C) rst and second coacting rollers on said first and second shafts,respectively, said strip material passing between said rollers in itsmovement along said path,

(D) means engaging said strip material at a location beyond said rollersand operative to continuously fplastioally deform said strip materialinto a first helical path winding successively around one of said shaftstoward the -free end of the latter,

(E) first and second forming rollers secured to said first and secondshafts adjacent their respective free ends, at least one of said formingrollers having first and second annular grooves therein, the stripmaterial being passed from said first helical path between said formingrollers with its (wire reinforced edge received in said first groove andbeing thereafter looped around the forming roller on said one shaft forrepassage between said forming rollers with its wire reinforced edgereceived in said second groove in a selected amount of overlapping withthe adhesive edge of said strip,

(F) and means for continuously counter rotating said shafts and therebysaid forming rollers,

(G) said first and second grooves being spaced apart axially by adistance different from the pitch of said first helical path so -thatsaid strip material is elastically constrained to achieve said selectedamount of overlapping.

19. An apparatus according to claim S, said engaging means comprising(A) a bending roller disposed ahead 'of said coacting rollers and havinga peripheral surface tracing an orbit intersecting the plane of saidstraight line path, whereby to engage lthe strip material as the lattermoves along said straight line path to bend it out of said plane formovement in an arcuate path, and

(B) a defiector member presenting a defiection surface extending acrossthe plane of said arcuate path at an obtuse angle thereto to engage saidstrip material as the latter moves along said arcuate path and twist itout of said arcuate path plane and into said first helical path.

11. An apparatus as defined in claim 1 wherein said first and secondgrooves are spaced apart axially by a distance less than the pitch ofsaid first helical path.

12. An apparatus as defined in claim 8 wherein said first and secondgrooves are spaced apart axially by `a distance less than the pitch ofsaid rst helical path.

13. An apparatus as defined in claim 9 wherein said first `and secondgrooves are spaced apart axially by a distance less than the pitch ofsaid first helical path.

References Cited by the Examiner UNITED STATES PATENTS 2,539,853 1/1951Meyers et al 156-143 2,759,521 S/1956 Hall et al. 156-429 3,192,0886/1965 Lariviere 156-171 X 3,219,738 1l/1965 Olson 156-143 X EARL M.BERGERT, Primary Examiner.

P. DIER, Assistant Examiner.

1. AN APPARATUS FOR FORMING A CONTINUOUS PRE-STRESSED FLEXIBLE HOSE FROMA CONTINUOUS FLEXIBLE STRIP HAVING A CONTINUOUS REINFORCING SPRING WIRESECURED THERETO SUBSTANTIALLY ADJACENT ONE EDGE THEREOF COMPRISING (A)MEANS FOR CONTINUOUSLY PLASTICALLY DEFORMING THE WIRE REINFORCED STRIPINTO A FIST HELICAL PATH, (B) FIRST AND SECOND FORMING ROLLERS, AT LEASTONE OF SAID ROLLERS HAVING FIRST AND SECOND ANNUALR GROOVES THEREIN. (C)SAID FORMING ROLLERS BEING MOUNTED FOR ROTATION ABOUT PARALLEL AXES, THEFLEXIBLE STRIP BEING PASSED FROM SAID FIRST HELICAL PATH BETWEEN SAIDROLLERS WITH ITS WIRE REINFORCED EDGE RECEIVED IN SAID FIRST GROOVE ANDBEING THERAFTER LOOPED AROUND ONE OF SAID ROLLERS WITH ITS WIREREINFORCED EDGE RECEIVED IN SAID SECOND GROOVE IN A SELECTED MOUNT OFOVERLAPPING WITH THE OTHER EDGE OF SAID STRIP, (D) AND MEANS FORCONTINOUSLY COUNTER ROTATING SAID ROLLERS, (E) SAID FIRST AND SECONDGROOVES BEING SPACED APART AXIALLY BY A DISTANCE DIFFERENT FROM THEPITCH OF SAID FIRST HELICAL PATH SO THAT SAID STRIP IS ELASTICALLYCONSTRAINED TO ACHIEVE SAID SELECTED AMOUNT OF OVERLAPPING.